Method for the froduction of normally liquid hydrocarbons from gastcus or lower boiling hydrocarbon matebials



Aug. 2, 1932. K, FRQUCH 1,869fi8i METHOD FOR THE PRODUCTION OF NORMALLYLIQUID HYDROCARBONS FROM GnsEOUs OR LOWER BOILING HYDROCARBON MATERIALSFiled March 24, 1930 QM {W gwwwtoz more specifically to a processlatented Aug; 2, i932 siren PER K. FBQLICH; O12 ELETH, NEW JERSEY,ELSSIGHUR T6 sacraments GE DWEQE? COMEANY, ACQEPQRATIQN @E" DEMWQEEMETHOD FOR THE'PRQDUC'IIQN GI? NORMALLY lLIQUm RQGMBQZBYSw FRUEEGarlaEE-QUtil 0E, IEWEE BQILIHG' HYIEEQGARBQN Application filed Marchat,

The present invention relates to an im= proved method for the productionof nor-' mally liquid hydrocarbons from gaseous or lower boilinghydrocarbon materials and for the production of liquid hydrocarbonsboiling within the range suitable for commercial gasoline from gaseousor low boiling hydrocarbons. My process will be fully understood from 19the following description read in conjunction with the drawing which isa semi-diagrammatic side elevation partly in section of the preferredform of the apparatus.

Large quantities of low boiling hydrocarbons such as ethane, propane,butane and the like, occur in natural or refinery gases and at thepresent time are largely used for fuel, line to the fact that suchhydrocarbons are either gaseous or boil at too low temperatures to beincluded in commercial gasolines. l have discovered a method by whichsuch materials may be converted into higher boiling products admirablysuited for use in internal combustion engines and for other uses forwhich products of the same boiling range, may be used.

My process consists in a series of steps as follows First the conversionof saturatedmae terials such as ethane, propane and butane into olefins,which is accompanied by the liberation of free hydrogen. -The secondstep comprises removal from this gaseous mixture of the free hydrogenand the third step comprises polymerization of hydrogen-free gas to formnormally liquid hydrocarbons suitable for commercial motor fuel. Each ofthe said steps will be separately described. The first, or cracking stepmay be carried out in any desired manner, for example; merely by heatingto a decomposition temperature say from approximately 600 to 1000 G.either with or without pressure and in the presencev or absence ofcatalysts, preferably nonferrous tubes or ferrous metal tubes con-;taining 8% of chromium or more. The preferred method, however, is thatdisclosed in: the co-pending application Serial No. 360,- 000 of thepresent inventor with B. O. Boeck-, eler hich was filed May 2, 1929.This process comprises dehydrogenation of hydrocarused in.

race, Serial No. ceases. I

bone by the use of certain catalytic agents at temperatures within theapproximate range of 450 (C. to 700 C. with or without pres sure.Metallic catalysts have been found satisfactory and the mixture ofmetallic oxides after reduction with methanol, hydrogen or hydrocarbonvapors or otherwise, are pre ferred although other types ofdehydrogenation catalysts may be used. Gatalysts containing zinc andanother metal which hasv two or more valences are particularlydesirable, such as 30 mol percent zinc, 10 mol per cent of chromium orother proportions of the same elements, or zinc and molybdenum ortungsten, vanadium and the like. The rate of flow of the gases in thisprocess is preterably very rapid, for example; above about two volumesof hydrocarbon vapor per min ute per volume of reaction space and undersuch conditions it is observed that twc or more atoms of hydrogen areremoved from the hydrocarbon molecule with substantially nodecomposition of the carbon structure, that is to say,,substantially nohydrocarbons of fewer carbon atoms are produced.

This process may be used on pure hydrocarbons or mixtures oil two ormore hydrocarbons and diluent gases including hydrogen, nitrogen,methane or other gases may be used. In this way the highest yield ofolefins and consequently the lowest yield of methane which forms as awaste product in the process is obtained.

The gas obtained from the first stew of my process comprises a mixtureof ole s, unreacted parafinic hydrocarbons, and hydrogen. Removal of themajor quantity of the free-hydrogen comprises the second step and thismay be accomplished in any desired mannor, for example; by liquefactionand subsequent rectification, or by other physics means, but it ispreferably accomplis ed by a process of preferential oxidation which isdis-v closed in the co-pending application Serial No. 438,651, entitledProcess for purifying gases filed on March 2t, 1930, by A. White and thepresentinventor.

In the operation of the preferential oxidation method the gas is mixedwith air or other gases containing free oxygen in substantiallyequivalent quantities required for complete combustion of the freehydrogen. The mixture is then passed over a catalytic material at atemperature within the range of about 250 to 450 C. with or withoutpressure. Means are preferably provided for removing the heat caused bythe combustion and this may be done by the use of small tubes or by theuse of tubes provided with fins or other heat radiating elements, or inthe case of larger tubes where relatively large volumes of ases are tobe treated, internal cooling wit? steam or other suitable means may beuse It has been found that copper shot or copper oxide is the mostsatisfactory catalytic material, but other materials such as lead,nickel, tin, bismuth or their oxides or equivalent metals whose oxidesare readily reducible by hydrogen within the specified temperature rangeor mixtures of such substances may be used. When the metals are used itis usually preferable to use temperatures in the up r end of the rangegiven, for example from 300 to 450 C. while if the oxides are used lowertemperatures such as 200 to 350 C. are more satisfactory. It is ofadvantage to remove as large a proportion of the free hydrogen as can bereadily caused to react without substantial combustion of the olefinsand it may be reduced below 5%. in the outlet mixture or even as low as3% or 1%. It is desirable to purify the gases of sulphur compounds priorto the partial oxidationstep since sulphurous impurities tend to poisonthe referential oxidation catalyst. The uri cation step may be carriedout prior to t e cracking step or after the cracking step and may beaccom lished either by a soda wash or by e uiva ent means.

The third or polymerization step may be carried out under atmosphericpressure or at higher pressures, for example; above 100 pounds persquare inch, but preferably in the range from 300 to 1000 pounds persquare inch. The temperature may vary considerably within theapproximate limits of 500 to 900 C. and it has been found that withhigher pressure it is generally desirable to use somewhat lowertemperatures. The time of reaction may vary widely, for example, fromless than 1 minute at higher temperatures to 25 or 30 minutes or longerat lower temperatures and contact materials may be used, preferably of ametallic character having a high heat conductivity in order to maintainuniform temperatures throughout the reaction.

chamber.

Using the present process, comprising the three steps described above,yields of 1 to 5 gallons of liquid products may be obtained per thousandcubic feet of propane or gases comprising, ethane, propane and butane.One half or more of the distillate isgenerally sufliciently low boilingfor commercial gaso- The gases are then passed either through adesulfurizer 5 or through a by-pass line 6 to the hydrogen remover 7 towhich air is admitted by means of compressor or blower 8 and manifold'9while steam may be admitted through line 10. From the hydrogen removerthe gases either pass through cooler 11 or through by-pass line 12 and,after compression by compressor 13 and passage through heat exchanger14, they come into the polymerizing chamber 15 which is followed by heatexchan er 14, condenser 16 and liquid receiver 1 The final liquidproducts are removed through line 18 and the gases through line 19.

As an example of the operation of my process propane is passed through atube of copper or other metal such as chrome steel or ceramic materialheated to a temperature of about 800 C. The outgoing gas has thefollowing composition:

Per cent 0 H 18 OH 37 oH.+o .H. 45

The gas is now compressed to a pressure of 600 pounds per square inchand passed through a chamber held at a temperature of 525C. at a rate soas to give a reaction time of about 30 minutes. About 61% of the olefinsreact and a yield of- 4.56 gallons of liquid material is obtained from1000 cubic feet of the inlet propane. About 4.26 gallons or over 90% ofthe total product boils within the range from 30 to 225 C. and has abromine number of 110. The material is light in color and afterfinishing in the ordinary nfethods well known in the petroleum industryis admirably suited for use in internal combustion engines, beingequivalent in anti-detonation value to a naphtha from an ordinary sweetcrude, such as Mid Conti- Per cent -nent crude, towhich 80% of benzolhas been added.

converting the paraifins to olefins The entire series of steps may becarried out at atmospheric or higher pressures, say 100 pounds persquare inch or if desired, one or more stepsqnay be at low the other orothers are accomplished at higher pressure. It is particularly desirableto conduct the cracking steps at atmospheric pressure or below 100pounds, scrub with alkali to remove sulphur, remove free hydrogen at thesame pressure and subsequently polymerize at pressures above 100 pounds.

My invention is not to be limited by any theory of the mechanism of thereactions nor to anyspecific example which may have been given forpurpose of illustration, but only by the following claims in which Iwish to claim all novelty inherent in my invention.

I claim:

1. An improved process for producing valuable higher boilinghydrocarbons from lower boiling saturated hydrocarbons of more than onecarbon atom, which comprises the steps of converting such saturatedhydrocarbons into unsaturates, removing the major quantity of'freehydrogen and polymeriz ng the olefins to form higher boilinghydrocarbons.

2. An improved process for converting low molecular paraffinichydrocarbons containing more than one carbon atom into higher molecularWeight hydrocarbons comprising and free hydrogen by the action of heat,removing the major quantity of free hydrogen by partial combustion andpolymerizing the olefin product in absence of substantial quantities offree hydrogen.

3. An improved process for obtaining normally liquid hydrocarbons fromgaseous hydrocarbons heavier than methane comprising the steps ofconverting a substantial part of the gaseous paraffins into olefins andhydrogen by application of heat at a decomposltion temperature, removingthe major quantity of free hydrogen by partial combustion in thepresence of a suitable catalytic agent and polymerizing the olefins inabsence 0 substantial quantities of hydrogen.

4. Process according to claim 3 in which the paraflinsare converted intoolefins by passage, at a temperature in excess of about 450 C. over asuitable dehydrogenation catalyst.

5. Process according to claim 3 in which the paraflins by passage at atemperature between 450 and 700 C. over reduced metal oxides.

6. Process according to claim 3 in which the mixture comprising olefinsand hydrogen is 'mixedwith a gas containing free oxygen and passed overa catalyst containing a metal whose oxide is readily reducible byhydrogen while at a temperature from 200 to 350 pressure, while areconverted largely to olefins whereby the hydrogen of free 9. Processaccording to claim 3 in which the olefin mixture is heated so as toleave not j more than 5% offree hydrogen and the resultin mixture ispolymerized at temperatures rom 500 to 990 C.

10. Process according to claim 3 in which the gas containing less than3% of free hy- .drogen is polymerized under pressure at temperaturesfrom 500 to 900 C. in a zone of substantially uniform temperatures.

11.. Process according to claim 3 in which the gas containing not morethan 3% of free hydrogen is polymerized under pressure in excess of 300pounds per square inch.

12. Process according to claim 3 in which the olefin containing gassubstantially free of hydrogen is polymerized by digestion underpressure in excess of 300 pounds per square inch for a period varyinginversely with temperature.

13. An improved process for obtaining valuable, hydrocarbon liquidssuitable for motor fuel from hydrocarbon gases rich in a constituentheavier than methane comprising partially dehydrogenating the gases byheat at temperature above 450 C. removing major quantity of freehydrogen by par-1 f under'pressure above 300 pounds per square inchandcooling and condensing normally liquid constituents.

PER K. FROLICH.

,DISOLAIMER v 1,869,681. Per K. Froli ch, Elizabeth, N. J. METHOD non'rnn Pn'oimc'rroN or I 'NORMALLY LIQUID -HYDROCARBONS FROM GAsEOUs 0RLOWER BOILING HXDROCARBON MATERIALS. Patent dated August 2, 1932.Disclaimer filed March 6, 1935, by the Assignee, Standard OilDevelopment Company.

v Hereby enters this disclaimer to that partof the claims in saidspecification which is in the following words, to wit: v v

1. An improved process for produclng valuable'hlgher boihng hydrocarbonsfrom c .lower boiling saturated hydrocarbons of more than one carbonatom, which comprises -the steps of converting such saturatedhydrocarbons into;unsaturates, removing the ma'or quantity of freehydrogen and polymerizing the olefines to form higher boilinghy carbons?[Qficial Gazette April 2, 1.935;]

